Power supply circuit for gas discharge lamps operating at a resonant frequency
First Claim
1. A power supply circuit for at least one power consuming lamp which is connected to a power supply, particularly for power consuming lamps such as at least one gas discharge lamp or glow lamp or flashlight lamp, comprising:
- a pulse width modulator;
a push-pull oscillator having electronic switches controlled by said pulse width modulator, and further having a resonant output transformer, having a control winding, a primary winding, and a secondary winding, wherein a resonant capacitor is coupled to said primary winding of the output transformer, and said secondary winding of the resonant output transformer is connected to at least one power consuming lamp;
said pulse width modulator having a pulse frequency which is tuned to the resonant frequency of the resonant output transformer of the push-pull oscillator;
a control circuit means for monitoring the resonant frequency of the output transformer and responding to a changed resonant frequency by adjusting the pulse frequency of the pulse width modulator to the changed resonant frequency, said control circuit means monitoring the resonant frequency of the output transformer by monitoring at least one of, (i) deviations from a resonant voltage form through said control winding of the primary circuit of the output transformer, (ii) the input current to the power supply circuit, and (iii) time periods leading to distortions in the sinusoidal oscillations of the resonant frequency; and
further wherein an input transformer is connected to the input of said primary winding of the output transformer, said input transformer having a first winding and a second winding, with said first winding of the input transformer being connected in series with said primary winding of the output transformer, and said second winding of the input transformer being connected with a diode and functioning as a free wheeling winding to the supply voltage.
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Accused Products
Abstract
A power supply circuit for any kind of loads or power consuming devices which are connected to an electrical power supply; especially lamps, such as at least one glow or gas discharge lamp, wherein a pulse width modulator controls electronic switches of a push-pull oscillator, and wherein the pulse frequency of the pulse width modulator is tuned to the resonant frequency of a resonant transformer of the push-pull oscillator which has the secondary side thereof connected to the gas discharge lamp. A control circuit monitors a current and/or voltage value and/or time value which is characteristic for the presence of the resonance and which, upon a change in the resonant frequency, will change the pulse frequency of the pulse width modulator to ensure operation at the new resonant frequency.
31 Citations
13 Claims
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1. A power supply circuit for at least one power consuming lamp which is connected to a power supply, particularly for power consuming lamps such as at least one gas discharge lamp or glow lamp or flashlight lamp, comprising:
- a pulse width modulator;
a push-pull oscillator having electronic switches controlled by said pulse width modulator, and further having a resonant output transformer, having a control winding, a primary winding, and a secondary winding, wherein a resonant capacitor is coupled to said primary winding of the output transformer, and said secondary winding of the resonant output transformer is connected to at least one power consuming lamp;
said pulse width modulator having a pulse frequency which is tuned to the resonant frequency of the resonant output transformer of the push-pull oscillator;
a control circuit means for monitoring the resonant frequency of the output transformer and responding to a changed resonant frequency by adjusting the pulse frequency of the pulse width modulator to the changed resonant frequency, said control circuit means monitoring the resonant frequency of the output transformer by monitoring at least one of, (i) deviations from a resonant voltage form through said control winding of the primary circuit of the output transformer, (ii) the input current to the power supply circuit, and (iii) time periods leading to distortions in the sinusoidal oscillations of the resonant frequency; and
further wherein an input transformer is connected to the input of said primary winding of the output transformer, said input transformer having a first winding and a second winding, with said first winding of the input transformer being connected in series with said primary winding of the output transformer, and said second winding of the input transformer being connected with a diode and functioning as a free wheeling winding to the supply voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
- a pulse width modulator;
Specification